Polymerizable liquid crystal compounds, polymerizable liquid crystal compositions, liquid crystalline polymers, phase difference film and display device

ABSTRACT

Provided is a polymerizable liquid crystal compound represented by formula (1). 
     
       
         
         
             
             
         
       
     
     An aspect can be exemplified, in which, in formula (1), W 1  is hydrogen or a substituent, A 1  is 1,4-phenylene, 1,4-cyclohexylene or naphthalene-2,6-diyl, Z 1  and Y 1  are a connecting group, m and n each are an integer from 0 to 7, in which an expression: 3≦m+n≦8 holds, Q 1  is a spacer, and PG is a polymerizable group.

TECHNICAL FIELD

The invention relates to a polymerizable liquid crystal compound forobtaining a phase difference film having high front contrast, apolymerizable liquid crystal composition containing the polymerizableliquid crystal compound and a liquid crystal polymer.

BACKGROUND ART

A liquid crystal polymer prepared by using a polymerizable liquidcrystal composition as a raw material can be utilized in a displaydevice having a film or a device consisting of an optically anisotropicfilm such as a phase difference film, an optical compensation film, areflection film, a selective reflection film, an antireflection film, aviewing angle compensation film, a liquid crystal alignment film, apolarizing device, a circularly polarizing device and an ellipticallypolarizing device.

For example, the phase difference film is used for displaying an imagewith high quality in a liquid crystal display device. A liquid crystalpolymer formed by curing the polymerizable liquid crystal compositionexhibits birefringence, and therefore can be used as the phasedifference film. A stretched polymer film exhibiting birefringence hasbeen so far used as the phase difference film. A study has beenconducted on applying the liquid crystal polymer as the phase differencefilm for the purpose of ease of film formation, achievement of thin filmin a film thickness and improvement of durability.

In the phase difference film formed of the liquid crystal polymer, anattempt has been made on immobilizing alignment in a state of a smecticphase for improving front contrast (Patent literature No. 1).

CITATION LIST Patent Literature

Patent literature No. 1: JP 2016-051178 A

SUMMARY OF INVENTION Technical Problem

In recent years, further improvement of display quality by achievinghigh definition of a liquid crystal display device has been required,and enhancement of front contrast than ever before has been requiredalso in a phase difference film.

An object of the invention is to provide a phase difference film havinghigh front contrast. Moreover, an object to be solved is to provide apolymerizable liquid crystal compound for preparing a phase differencefilm having high front contrast, a polymerizable liquid crystalcomposition containing the polymerizable liquid crystal compound and aliquid crystal polymer.

Solution to Problem

The present inventors have found that a phase difference film havinghigh front contrast can be provided by using a liquid crystal polymerobtained by curing a polymerizable liquid crystal composition containinga specific polymerizable liquid crystal compound, and thus havecompleted the invention.

Item 1. A polymerizable liquid crystal compound, represented by formula(1):

wherein, in formula (1),

W¹ is independently hydrogen, fluorine, alkyl having 1 to 5 carbons,alkenyl having 2 to 5 carbons or fluoroalkyl having 1 to 5 carbons,

A¹ is independently 1,4-phenylene, 1,4-cyclohexylene ornaphthalene-2,6-diyl, and in the rings, at least one hydrogen may bereplaced by fluorine, chlorine, trifluoromethyl, alkyl having 1 to 5carbons, alkoxy having 1 to 5 carbons, alkoxycarbonyl having 1 to 5carbons or alkanoyl having 1 to 5 carbons,

Z¹ is independently —CH₂CH₂—, —COO—, —OCO—, —CH₂O—, —OCH₂—, —OCH₂CH₂O—,—CH═CHCOO—, —OCOCH═CH—, —CH₂CH₂COO—, —OCOCH₂CH₂—, —CH₂CH₂OCO— or—COOCH₂CH₂—,

m and n are independently an integer from 0 to 7, in which anexpression: 3≦m+n≦8 holds,

Y¹ is independently a single bond, —O—, —COO—, —OCO— or —OCOO—,

Q¹ is independently an single bond or alkylene having 1 to 20 carbons,and in the alkylene, at least one piece of —CH₂— may be replaced by —O—,—OCO—, —OCO—, —CH═CH— or —CH≡CH—, and

PG is independently a functional group represented by any one of formula(PG-1) to formula (PG-9):

wherein, in formula (PG-1) to formula (PG-9), R¹ is independentlyhydrogen, halogen, methyl, ethyl or trifluoromethyl.

Item 2. The polymerizable liquid crystal compound according to item 1,wherein at least one of W¹ is alkyl having 1 to 5 carbons, and at leastone of Z¹ is —CH₂CH₂COO— or —OCOCH₂CH₂—.

Item 3. The polymerizable liquid crystal compound according to item 1 or2, wherein PG is a functional group represented by formula (PG-1).

Item 4. The polymerizable liquid crystal compound according to any oneof items 1 to 3, wherein at least one of Z¹ is —CH₂CH₂COO—, and at leastone of Z¹ is —OCOCH₂CH₂—.

Item 5. A polymerizable liquid crystal composition, containing thepolymerizable liquid crystal compound according to any one of items 1 to4.

Item 6. The polymerizable liquid crystal composition according to item5, containing 5 to 70 parts by weight of a polymerizable liquid crystalcompound represented by formula (1) when the total amount of thepolymerizable liquid crystal compound in a polymerizable liquid crystalcomposition is taken as 100 parts by weight.

Item 7. A liquid crystal polymer, formed by curing the polymerizableliquid crystal composition according to item 5 or 6.

Item 8. The liquid crystal polymer according to item 7, wherein liquidcrystal molecules are immobilized in a state in which the liquid crystalmolecules are aligned by a photoalignment film.

Item 9. A phase difference film, including the liquid crystal polymeraccording to item 7 or 8.

Item 10. A display device, having the liquid crystal polymer accordingto item 7 or 8.

Advantageous Effects of Invention

A liquid crystal polymer having high front contrast can be produced byadding, to a polymerizable liquid crystal composition serving as a rawmaterial of the liquid crystal polymer, a polymerizable liquid crystalcompound characterized by having, as shown in formula (1), a fluoreneskeleton and four or more ring structures of a monocycle and a fusedring in total.

DESCRIPTION OF EMBODIMENTS

In the invention, “front contrast” means a value obtained by dividing(luminance in a crossed Nicol state) by (luminance in a parallel Nicolstate) upon arranging a liquid crystal polymer between two polarizingplates.

In the invention, “crossed Nicol state” means a state in whichpolarization axes of polarizing plates arranged facing each other areorthogonally crossed.

In the invention, “parallel Nicol state” means a state in whichpolarization axes of polarizing plates arranged facing each other arematched.

In the invention, “An” means birefringence of a liquid crystal polymer.

In the invention, “compound (X)” means a compound represented by formula(X). Here, X in “compound (X)” means a text, a numerical character, asymbol or the like.

In the invention, “liquid crystal compound” is a generic term for acompound that has a liquid crystal phase, and a compound that can beused as a component of a liquid crystal composition upon being mixedwith any other liquid crystal compound even if the compound has noliquid crystal phase alone.

In the invention, “polymerizable functional group” means a functionalgroup that, when a compound has the group therein, is polymerized by ameans such as light, heat and a catalyst to change the compound into apolymer having larger molecular weight.

In the invention, “monofunctional compound” means a compound having onepolymerizable functional group.

In the invention, “polyfunctional compound” means a compound having aplurality of polymerizable functional groups.

In the invention, “X functional compound” means a compound having Xpieces of polymerizable functional groups.

Here, X in “X functional compound” represents an integer.

In the invention, “polymerizable compound” means a compound having atleast one polymerizable functional group.

In the invention, “polymerizable liquid crystal compound” means acompound being a liquid crystal compound and a polymerizable compound.

In the invention, “non-liquid crystal polymerizable compound” means apolymerizable compound being not a liquid crystal compound.

In the invention, “polymerizable liquid crystal composition” means acomposition containing a polymerizable compound and a liquid crystalcompound, or a composition containing “polymerizable liquid crystalcompound.”

In the invention, “liquid crystal polymerization film” means a portionof a polymer of the polymerizable liquid crystal composition, obtainedby polymerizing the polymerizable liquid crystal composition on asubstrate.

In the invention, “liquid crystal polymer with a substrate” means amaterial containing a substrate, obtained by polymerizing apolymerizable liquid crystal composition on the substrate.

In the invention, “liquid crystal polymer” is a generic term for aliquid crystal polymerization film and a liquid crystal polymer with asubstrate.

In the invention, “tilt angle” means an angle between a direction ofalignment of liquid crystal molecules and a plane of a supportsubstrate.

In the invention, “homogeneous alignment” means alignment with the tiltangle from 0 degrees to 5 degrees.

In the invention, “homeotropic alignment” means alignment with the tiltangle from 85 degrees to 90 degrees.

In the invention, “tilt alignment” means a state in which a direction ofalignment of liquid crystal molecules in a major axis direction rises upvertically from parallel relative to a substrate accordingly as theliquid crystal molecules are separated from the substrate.

In the invention, “twist alignment” means a state in which a directionof alignment of liquid crystal molecules in a major axis direction isparallel to a substrate, and the liquid crystal molecules are twistedstepwise with a helical axis as a center accordingly as the liquidcrystal molecules are separated from the substrate.

In the invention, “room temperature” means a temperature from. 15° C. to35° C.

When the functional group described below is described in the chemicalformula, a wavy line part means a position of bonding with thefunctional group. C described below herein represents an arbitrary atomor functional part.

Polymerizable Liquid Crystal Compound

From a polymerizable liquid crystal composition containing compound (1)according to the invention, a liquid crystal polymer having largebirefringence, and high front contrast can be produced.

Even if the polymerizable liquid crystal composition containing compound(1) according to the invention contains a large amount of polymerizableliquid crystal compound, no crystal is formed in the polymerizableliquid crystal composition even after a solvent is removed. Moreover, aliquid crystal polymer having no alignment defect can be obtained byusing the polymerizable liquid crystal composition as a raw material. Inthe liquid crystal polymer, retardation Re is not varied depending on anincident point in an incidence plane of the liquid crystal polymer.

In formula (1) described above, W¹ is independently hydrogen, fluorine,alkyl having 1 to 5 carbons, alkenyl having 2 to 5 carbons orfluoroalkyl having 1 to 5 carbons. When at least one of W¹ is alkylhaving 1 to 5 carbons, the liquid crystal phase in the polymerizableliquid crystal composition is easily developed, and phase separationfrom any other liquid crystal compound and an organic solvent in thepolymerizable liquid crystal composition is hard to be caused, andtherefore such a case is further preferred.

A¹ is independently 1,4-phenylene, 1,4-cyclohexylene ornaphthalene-2,6-diyl, and in the rings, at least one hydrogen may bereplaced by fluorine, chlorine, trifluoromethyl, alkyl having 1 to 5carbons, alkoxy having 1 to 5 carbons, alkoxycarbonyl having 1 to 5carbons or alkanoyl having 1 to 5 carbons.

In formula (1), Z¹ is independently —CH₂CH₂—, —COO—, —OCO—, —CH₂O—,—OCH₂—, —OCH₂CH₂O—, —CH═CHCOO—, —OCOCH═CH—, —CH₂CH₂COO—, —OCOCH₂CH₂—,—CH₂CH₂OCO— or —COOCH₂CH₂—. When at least one of Z¹ is —CH₂CH₂COO— or—OCOCH₂CH₂—, phase separation from any other liquid crystal compound andthe organic solvent in the polymerizable liquid crystal composition ishard to be caused, and therefore such a case is further preferred.

Then, m and n are independently an integer from 0 to 7, and anexpression: 3≦m+n≦8 holds. In order to enhance the front contrast, anexpression: m+n≧3 preferably holds, and in order to achieve difficultyin the phase separation from any other liquid crystal compound and theorganic solvent in the polymerizable liquid crystal composition, anexpression: m+n≦8 preferably holds.

In formula (1), Y¹ is independently a single bond, —O—, —COO—, —OCO— or—OCOO—, and Q¹ is independently an single bond or alkylene having 1 to20 carbons, and in the alkylene, at least one piece of —CH₂— may bereplaced by —O—, —OCO— or —OCO—. When Q¹ is alkylene having 1 to 20carbons, the liquid crystal phase of the polymerizable liquid crystalcomposition is easily developed, and the phase separation from any otherliquid crystal compound and the organic solvent is hard to be caused.

PG is independently a functional group represented by any one of formula(PG-1) to formula (PG-9).

The functional group represented by formula (PG-1), formula (PG-2),formula (PG-8) and formula (PG-9) has an electron withdrawing group inalkene, and therefore is a polymerizable functional group that ispolymerized by various means to change the compound to a polymer havinglarger molecular weight.

The functional group represented by formula (PG-3) to formula (PG-7) hasan ether ring having a strain, and therefore is a polymerizablefunctional group that is polymerized by various means to change thecompound to a polymer having larger molecular weight.

In formula (PG-1) to formula (PG-9), R¹ is independently hydrogen,halogen, methyl, ethyl or trifluoromethyl. The halogen is preferablyfluorine, chlorine, bromine or iodine.

As the functional group represented by formula (PG-1) to formula (PG-9),a suitable functional group can be selected according to conditions ofproducing a film. For example, when a film is prepared by photo-curingthat is ordinarily used, in view of high curability, solubility in asolvent, ease of handling and so forth, an acrylic group, a methacrylicgroup or the like represented by formula (PG-1) is preferred.

In the polymerizable liquid crystal compound represented by formula (1),in view of compatibility with other liquid crystal compounds and theorganic solvent, preferred examples include a compound represented byformula (1-1-1) to formula (1-1-10) and formula (1-2-1) to formula(1-2-7) each.

In formula (1-1-1) to formula (1-1-10) or formula (1-2-1) to formula(1-2-7), Y¹ is independently a single bond, —O—, —COO—, —OCO— or —OCOO—,Q¹ is independently an single bond or alkylene having 1 to 20 carbons,and in the alkylene, at least one piece of —CH₂— may be replaced by —O—,—OCO— or —OCO—, and PG is independently any one of functional groupsrepresented by formula (PG-1) to formula (PG-9) described above.

Compound (1) can be synthesized by combining a method of publicly-knownsynthetic organic chemistry. For example, compound (1) can besynthesized according to a reaction scheme shown in Example 1 describedbelow by using, as a starting material, a material synthesized in amanner similar to a method described in ACS Medicinal Chemistry Letters,2010, 1(7), pp 345-349.

Polymerizable Liquid Crystal Composition

A polymerizable liquid crystal composition of the invention contains oneor more compound (1). From a viewpoint of improvement of front contrastcharacteristics, when the total amount of the polymerizable liquidcrystal compound in the polymerizable liquid crystal composition takenas 100 parts by weight, the polymerizable liquid crystal compositionpreferably contains 5 to 70 parts by weight of compound (1), and furtherpreferably contains 10 to 50 parts by weight of compound (1). Moreover,the polymerizable liquid crystal composition of the invention preferablycontains 1.5 to 50% by weight of compound (1), and further preferablycontains 3 to 30% by weight of compound (1) based on the total amount ofthe polymerizable liquid crystal composition.

The polymerizable liquid crystal composition of the invention maycontain a polymerizable liquid crystal compound other than thepolymerizable liquid crystal compound represented by compound (1). As anexample of the polymerizable liquid crystal compound, from viewpoints ofability of occurrence of the liquid crystal phase of the polymerizableliquid crystal composition, and compatibility with compound (1) and theorganic solvent; a compound represented by formula (M) described belowis preferred.

In formula (M),

A^(M) is independently 1,4-phenylene, 1,4-cyclohexylene,naphthalene-2,6-diyl or fluorene-2,7-diyl, in which, in 1, 4-phenylene,naphthalene-2,6-diyl or fluorene-2,7-diyl, at least one hydrogen may bereplaced by fluorine, chlorine, cyano, formyl, alkyl having 1 to 5carbons, alkoxy having 1 to 5 carbons, alkenyl having 2 to 5 carbons,alkoxycarbonyl having 1 to 5 carbons, alkanoyl having 1 to 5 carbons,fluoroalkyl having 1 to 5 carbons or a group represented by—Y^(M)-Q^(M)-P^(M),

Z^(M) is independently a single bond, —CH₂CH₂—, —COO—, —OCO—, —C≡C—,—CH═CHCOO—, —OCOCH═CH—, —CH₂CH₂COO—, —OCOCH₂CH₂—, —CH₂CH₂OCO— or—COOCH₂CH₂—,

a is an integer of 1 or 2,

W^(M) is independently hydrogen, fluorine, chlorine, formyl, alkylhaving 1 to 5 carbons, alkenyl having 2 to 5 carbons, alkoxycarbonylhaving 1 to 5 carbons, alkanoyl having 1 to 5 carbons or fluoroalkylhaving 1 to 5 carbons,

Y^(M) is independently a single bond, —O—, —COO—, —OCO— or —OCOO—,

Q^(M) is independently a single bond or alkylene having 1 to 20 carbons,and in the alkylene, at least one piece of —CH₂— may be replaced by —O—,—OCO—, —OCO—, —CH═CH— or —CH≡CH—,

P^(M) is independently a functional group represented by any one offormula (PG-1) to formula (PG-9), and

R^(M) is fluorine, chlorine, cyano, alkyl having 1 to 5 carbons, alkoxyhaving 2 to 5 carbons, alkenyl having 1 to 5 carbons, alkoxycarbonylhaving 1 to 5 carbons, alkanoyl having 1 to 5 carbons, fluoroalkylhaving 1 to 5 carbons or a functional group represented by any one offormula (PG-1) to formulas (PG-9).

In formula (PG-1) to formula (PG-9), R¹ is independently hydrogen,halogen, methyl, ethyl or trifluoromethyl. The halogen is preferablyfluorine, chlorine, bromine or iodine.

In formula (M), when R^(M) is fluorine, chlorine, cyano, alkyl having 1to 5 carbons, alkoxy having 1 to 5 carbons, alkenyl having 2 to 5carbons, alkoxycarbonyl having 1 to 5 carbons, alkanoyl having 1 to 5carbons or fluoroalkyl having 1 to 5 carbons, compound (M) is amonofunctional compound.

When compound (M) is the monofunctional compound, in the polymerizableliquid crystal composition to which compound (M) is added, a liquidcrystal temperature range, optical characteristics and alignability areeasily controlled. If an amount of addition of compound (M) being themonofunctional compound is large, the polymerizable liquid crystalcomposition tends to be high in the tilt angle, and homeotropicalignment is easily obtained. When R^(M) is not the functional grouprepresented by any one of formula (PG-1) to formulas (PG-9), compound(M) is formed into the monofunctional compound.

Addition of the polyfunctional compound to the polymerizable liquidcrystal composition results in improving mechanical strength or chemicalresistance of the liquid crystal polymer, or both thereof. For example,a polymer of the polymerizable liquid crystal composition to whichcompound (M) being a bifunctional compound is added is formed into athree-dimensional structure. If compound (M) being the bifunctionalcompound is added thereto, the polymer of the polymerizable liquidcrystal composition, formed into the three-dimensional structure,becomes harder. In addition, when R^(M) is the functional grouprepresented by any one of formula (PG-1) to formulas (PG-9), compound(M) is formed into the bifunctional compound.

If improvement of the front contrast of the liquid crystal polymer,induction of the liquid crystal phase of the polymerizable liquidcrystal composition serving as the raw material of the liquid crystalpolymer, and phase separation from any other liquid crystal compound andthe organic solvent in the composition are taken into consideration, atotal of the compounds represented by formula (M) in the polymerizableliquid crystal composition is preferably 30 to 95% by weight, andfurther preferably 30 to 70% by weight, based on the total weight of thecompounds represented by formula (1) and formula (M).

Examples of a preferred compound represented by formula (M) will beshown below.

In formulas (M-1-1) to (M-1-18), formulas (M-2-1) to (M-2-30) andformulas (M-3-1) to (M-3-8), R² is independently hydrogen or methyl, anda is independently an integer from 1 to 12.

The polymerizable liquid crystal composition of the invention is coatedonto a plastics substrate subjected to alignment treatment such asrubbing treatment or a support substrate a surface of which is coveredwith a thin film of plastic to form a film into a homogeneously-alignedor tilt-aligned liquid crystal polymer.

Additives to Polymerizable Liquid Crystal Composition

One kind or more kinds of additives may be added to the polymerizableliquid crystal composition of the invention.

Addition of a surfactant to the polymerizable liquid crystal compositionresults in improving smoothness of the liquid crystal polymer. Additionof a nonionic surfactant to the polymerizable liquid crystal compositionresults in further improving the smoothness of the liquid crystalpolymer. The nonionic surfactant is effective in suppressing the tiltalignment on a side of an air interface of the liquid crystal polymer.

A silicone-based nonionic surfactant, a fluorine-based nonionicsurfactant, a vinyl-based nonionic surfactant, a hydrocarbon-basednonionic surfactant or the like is the nonionic surfactant.

The surfactant is effective in uniting with other polymerizable liquidcrystal compounds, and therefore the surfactant being the polymerizablecompound is preferably added to the polymerizable liquid crystalcomposition. From a viewpoint of reactivity with the polymerizableliquid crystal compound, as the surfactant, a surfactant to start apolymerization reaction with ultraviolet light is preferred.

The liquid crystal polymer is easily uniformly aligned, andapplicability of the polymerizable liquid crystal composition isimproved, and therefore the surfactant in the polymerizable liquidcrystal composition is preferably 0.0001 to 0.5% by weight, and furtherpreferably 0.01 to 0.2% by weight, based on the total amount of thepolymerizable liquid crystal composition.

Specific examples of the surfactant include an ionic surfactant, asilicone-based nonionic surfactant, a fluorine-based nonionicsurfactant, a vinyl-based nonionic surfactant and other nonionicsurfactants.

Specific examples of the ionic surfactant include a titanate-basedcompound, imidazoline, a quaternary ammonium salt, alkylamine oxide, apolyamine derivative, a polyoxyethylene-polyoxypropylene condensate,polyethylene glycol and ester thereof, sodium lauryl sulfate, ammoniumlauryl sulfate, lauryl sulfate amines, alkyl-substituted aromaticsulfonate, alkyl phosphate, an aliphatic or aromatic sulfonicacid-formalin condensate, lauryl amidopropyl betaine, laurylaminoacetate betaine, polyethyleneglycol fatty acid esters,polyoxyethylene alkylamine, perfluoroalkyl sulfonate and perfluoroalkylcarboxylate.

Specific examples of the silicone-based nonionic surfactant include astraight-chain polymer formed of siloxane bond, and a compound in whichan organic group such as polyether and a long-chain alkyl is introducedinto a side chain and/or a terminal.

Specific examples of the fluorine-based nonionic surfactant include acompound having a perfluoroalkyl group having 2 to 7 carbons or aperfluoro alkenyl group having 2 to 7 carbons.

Specific examples of the vinyl-based nonionic surfactant include a(meth)acrylic polymer having a weight average molecular weight of 1,000to 1,000,000.

Addition of the surfactant having the polymerizable functional group tothe polymerizable liquid crystal composition results in improvingsurface hardness of the liquid crystal polymer.

The polymerizable liquid crystal composition of the invention maycontain the non-liquid crystal polymerizable compound. In order tomaintain the liquid crystal phase, the total weight of the non-liquidcrystal polymerizable compound in the polymerizable liquid crystalcomposition is preferably one tenth or less of the total weight of thepolymerizable compound in the polymerizable liquid crystal composition.

Reinforcement of the mechanical strength of the liquid crystal polymer,or improvement of the chemical resistance or both thereof can beexpected by addition of a compound having two or more polymerizablegroups to the polymerizable liquid crystal composition.

Specific examples of the non-liquid crystal polymerizable compoundinclude a compound having one or two or more vinyl-based polymerizablegroups.

Improvement of adhesion between the polymerizable liquid crystalcomposition and the substrate can be expected by addition of thenon-liquid crystal polymerizable compound having a polar group in a sidechain and/or a terminal to the polymerizable liquid crystal composition.

Specific examples of the non-liquid crystal polymerizable compound beingthe monofunctional compound include styrene, nucleus-substitutedstyrene, acrylonitrile, vinyl chloride, vinylidene chloride,vinylpyridine, N-vinyl pyrrolidone, vinylsulfonic acid, fatty acidvinyl, α, β-ethylenic unsaturated carboxylic acid, alkyl ester of(meth)acrylic acid in which the number of carbon atoms is 1 to 18,hydroxy alkyl ester of (meth)acrylic acid in which the number of carbonatoms of hydroxyalkyl is 1 to 18, amino alkyl ester of (meth)acrylicacid in which the number of carbon atoms of amino alkyl is 1 to 18,ether oxygen-containing alkyl ester of (meth)acrylic acid in which thenumber of carbon atoms of ether oxygen-containing alkyl is 3 to 18,N-vinylacetamide, vinyl p-t-butyl benzoate, vinylN,N-dimethylaminobenzoate, vinyl benzoate, vinyl pivalate, vinyl2,2-dimethylbutanoate, vinyl 2,2-dimethylpentanoate, vinyl2-methyl-2-butanoate, vinyl propionate, vinyl stearate, vinyl2-ethyl-2-methylbutanoate, dicyclopentanyloxyl ethyl (meth)acrylate,isobornyloxyl ethyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl(meth)acrylate, dimethyladamantyl (meth)acrylate, dicyclopentanyl(meth)acrylate, dicyclopentenyl (meth)acrylate, 2-acryloyloxy ethylsuccinate, 2-acryloyloxyethyl hexahydrophthalic acid, 2-acryloyloxyethylphthalic acid, 2-acryloyloxyethyl-2-hydroxyethyl phthalic acid,2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acidphosphate, polyethylene glycol having a polymerization degree of 2 to100, polypropylene glycol, mono(meth)acrylate or di(meth)acrylate ofpolyethylene glycol such as a copolymer between ethylene oxide andpropylene oxide, or polyethylene glycol having a polymerization degreeof 2 to 100 and capped with alkyl having 1 to 6 carbons at a terminal,and mono(meth)acrylate of polyalkylene glycol being a copolymer amongpolypropylene glycol, ethylene oxide and propylene oxide. Specificexamples of “fatty acid vinyl” herein include vinyl acetate. Specificexamples of “α,β-ethylenic unsaturated carboxylic acid” herein includeacrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconicacid. Specific examples of “ether oxygen-containing alkyl ester of(meth)acrylic acid in which the number of carbon atoms of etheroxygen-containing alkyl is 3 to 18” include methoxyethyl ester,ethoxyethyl ester, methoxypropyl ester, methylcarbyl ester, ethylcarbylester and butylcarbyl ester.

Specific examples of the non-liquid crystal polymerizable compound beingthe bifunctional compound include 1,4-butanediol diacrylate,1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, neopentyl glycoldiacrylate, dimethylol tricyclodecane diacrylate, triethylene glycoldiacrylate, dipropylene glycol diacrylate, tripropylene glycoldiacrylate, tetraethylene glycol diacrylate, bisphenol A EO-addeddiacrylate, bisphenol A glycidyl diacrylate, polyethylene glycoldiacrylate and a methacrylate compound thereof.

Specific examples of the non-liquid crystal polymerizable compound ofthe polyfunctional compound being not the bifunctional compound includepentaerythritol triacrylate, trimethylolpropane triacrylate, trimethylolEO-added triacrylate, trisacryloyloxyethyl phosphate,tris(acryloyloxyethyl)isocyanurate, alkyl-modified dipentaerythritoltriacrylate, EO-modified trimethylolpropane tricrylate, PO-modifiedtrimethylolpropane triacrylate, pentaerythritol tetraacrylate,alkyl-modified dipentaerythritol tetraacrylate, ditrimethylolpropanetetraacrylate, dipentaerythritol hexaacrylate,dipentaerythritolmonohydroxy pentaacrylate, alkyl-modifieddipentaerythritol pentaacrylate, pentaerythritol trimetaacrylate,trimethylolpropane trimethacrylate, trimethylol EO-addedtrimetaacrylate, trismethacryloyloxy ethyl phosphate,trismethacryloyloxy ethyl isocyanurate, alkyl-modified dipentaerythritoltrimetaacrylate, EO-modified trimethylolpropane trimethacrylate,PO-modified trimethylolpropane trimethacrylate, pentaerythritoltetramethacrylate, alkyl-modified dipentaerythritol tetramethacrylate,ditrimethylolpropane tetramethacrylate, dipentaerythritolhexamethacrylate, dipentaerythritolmonohydroxy pentamethacrylate andalkyl-modified dipentaerythritol pentamethacrylate. Addition of apolymerizable compound having a bisphenol structure or cardo structureto the polymerizable liquid crystal composition results in inducingimprovement of hardness of the polymer and homeotropic alignment of theliquid crystal polymer.

Specific examples of a polymerizable fluorene derivative having thecardo structure include compounds (α-1) to (α-3).

In formula (α-1) to (α-3), R^(α) is independently hydrogen or methyl,and s is independently an integer from 0 to 4.

Addition of a polymerization initiator results in optimizing a rate ofpolymerization of the polymerizable liquid crystal composition. Specificexamples of the polymerization initiator include a photoradicalinitiator.

Specific examples of the photoradical initiator include1-hydroxy-cyclohexyl-phenyl-ketone,2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-hydroxycyclohexylphenylketone, 2,2-dimethoxy-1,2-diphenylethane-1-one,p-methoxyphenyl-2,4-bis(trichloromethyl)triazine,2-(p-butoxystyryl)-5-trichloromethyl-1,3,4-oxadiazole, 9-phenylacridine,9,10-benzphenazine, a benzophenone-Michler's ketone mixture, ahexaarylbiimidazole-mercaptobenzimidazole mixture,1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, benzyl dimethylketal, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1-one, a2,4-diethylxanthone-methyl p-dimethylaminobenzoate mixture, abenzophenone-methyltriethanolamine mixture, Adeka Optomer N-1919, AdekaCruise NCI-831, Adeka Cruise NCI-930, Irgacure 127, Irgacure 369,Irgacure 379, Irgacure 500, Irgacure 754, Irgacure 784, Irgacure 819,Irgacure 907, Irgacure 1300, Irgacure 1700, Irgacure 1800, Irgacure1850, Irgacure 1870, Irgacure 2959, Irgacure OXE01, Irgacure OXE02,Darocur 4265, Darocur MBF and Darocur TPO. Here, Adeka, Irgacure andDarocur are registered trademarks.

The total weight of a photoradical polymerization initiator in thepolymerizable liquid crystal composition is preferably 0.01 to 10% byweight, further preferably 0.1 to 4% by weight, and still furtherpreferably 0.5 to 4% by weight, based on the total amount of thepolymerizable liquid crystal composition.

A sensitizer may be added to the polymerizable liquid crystalcomposition together with the photoradical polymerization initiator.Specific examples of the sensitizer include isopropylthioxanthone,diethylthioxanthone, ethyl-4-dimethylaminobenzoate and2-ethylhexyl-4-dimethylaminobenzoate.

A rate of reaction of the polymerizable liquid crystal compound and alength of a chain of the polymer in the liquid crystal polymerizationfilm can be adjusted by addition of a chain transfer agent to thepolymerizable liquid crystal composition.

The rate of reaction of the polymerizable liquid crystal compound isreduced by increase in an amount of the chain transfer agent. The lengthof the chain of the polymer is decreased by increase in the amount ofthe chain transfer agent.

Specific examples of the chain transfer agent include a thiol derivativeand a styrene dimer derivative.

Specific examples of the thiol derivative include a thiol derivativebeing a monofunctional compound and a thiol derivative being apolyfunctional compound.

Specific examples of the thiol derivative being the monofunctionalcompound include dodecanethiol and 2-ethylhexyl-(3-mercapto) propionate.Specific examples of the thiol derivative being the polyfunctionalcompound include trimethylolpropane tris(3-mercaptopropionate),pentaerythritol tetrakis(3-mercaptopropionate),1,4-bis(3-mercaptobutyryloxy) butane, pentaerythritoltetrakis(3-mercaptobutyrate) and1,3,5-tris(3-mercaptobutyloxyethyl)-1,3,5-triazine-2,4,6 (1H, 3H,5H)-trione.

Specific examples of the styrene dimer-based chain transfer agentinclude 2,4-diphenyl-4-methyl-1-pentene and 2,4-diphenyl-1-butene.

Addition of a polymerization preventive to the polymerizable liquidcrystal composition results in preventing start of polymerization duringstorage of the polymerizable liquid crystal composition. Specificexamples of the polymerization preventive include (1) 2,5-di(t-butyl)hydroxytoluene, hydroquinone, methylene blue, diphenyl picryl hydrazide,phenothiazine and N,N-dimethyl-4-nitrosoaniline, each being a compoundhaving a nitroso group, and (2) o-hydroxybenzophenone,2H-1,3-benzothiazine-2,4-(3H)dione, each being a benzothiazinederivative.

Addition of a polymerization inhibitor to the polymerizable liquidcrystal composition results in suppressing the polymerization reactionin the polymerizable liquid crystal composition by generation ofradicals in the polymerizable liquid crystal composition. Addition ofthe polymerization inhibitor results in improving storage stability ofthe polymerizable liquid crystal composition.

Specific examples of the polymerization inhibitor include (1) aphenol-based antioxidant, (2) a sulfur-based antioxidant, (3) aphosphoric acid-based antioxidant and (4) an amine-based antioxidant.From a viewpoint of compatibility with the polymerizable liquid crystalcomposition or transparency of the liquid crystal polymer, aphenol-based antioxidant is preferred. From a viewpoint of thecompatibility, as the phenol-based antioxidant, a compound having at-butyl group in an ortho position of a hydroxy group is preferred.

Addition of an ultraviolet light absorber to the polymerizable liquidcrystal composition results in improving weather resistance of thepolymerizable liquid crystal composition.

Addition of alight stabilizer to the polymerizable liquid crystalcomposition results in improving the weather resistance of thepolymerizable liquid crystal composition.

Addition of the antioxidant to the polymerizable liquid crystalcomposition results in improving the weather resistance of thepolymerizable liquid crystal composition.

Addition of a silane coupling agent to the polymerizable liquid crystalcomposition results in improving adhesion between the substrate and theliquid crystal polymerization film.

In order to facilitate coating, a solvent is preferably added to thepolymerizable liquid crystal composition.

Specific examples of a component of the solvent include ester, anamide-based compound, alcohol, ether, glycol monoalkyl ether, aromatichydrocarbon, halogenated aromatic hydrocarbon, aliphatic hydrocarbon,halogenated aliphatic hydrocarbon, alicyclic hydrocarbon, ketone and anacetate-based solvent.

The amide-based compound means a compound having an amide group, andserving as the component of the solvent. The acetate-based solvent meansa compound having an acetate structure, and serving as the component ofthe solvent.

Specific examples of the ester include alkyl acetate, ethyltrifluoroacetate, alkyl propionate, alkyl butyrate, dialkyl malonate,alkyl glycolate, alkyl lactate, monoacetin, γ-butyrolactone andγ-valerolactone.

Specific examples of “alkyl acetate” herein include methyl acetate,ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate,3-methoxybutyl acetate, isobutyl acetate, pentyl acetate and isopentylacetate. Specific examples of “alkyl propionate” herein include methylpropionate, methyl 3-methoxypropionate, ethyl propionate, propylpropionate and butyl propionate. Specific examples of “alkyl butyrate”herein include methyl butyrate, ethyl butylate, butyl butyrate, isobutylbutyrate and propyl butyrate. Specific examples of “dialkyl malonate”herein include diethyl malonate. Specific examples of “alkyl glycolate”herein include methyl glycolate and ethyl glycolate. Specific examplesof “alkyl lactate” herein include methyl lactate, ethyl lactate,isopropyl lactate, n-propyl lactate, butyl lactate and ethylhexyllactate.

Specific examples of the amide-based compound includeN-methyl-2-pyrrolidone, N,N-dimethylacetamide, N-methylpropionamide,N,N-dimethylformamide, N,N-diethylformamide, N,N-diethylacetamide,N,N-dimethylacetamide dimethyl acetal, N-methylcaprolactam anddimethylimidazolidinone.

Specific examples of the alcohol include methanol, ethanol, 1-propanol,2-propanol, 1-methoxy-2-propanol, t-butyl alcohol, sec-butyl alcohol,butanol, 2-ethylbutanol, n-hexanol, n-heptanol, n-octanol, 1-dodecanol,ethylhexanol, 3,5,5-trimethylhexanol, n-amyl alcohol,hexafluoro-2-propanol, glycerol, ethylene glycol, diethylene glycol,triethylene glycol, tetraethylene glycol, propylene glycol, dipropyleneglycol, tripropylene glycol, hexylene glycol, 1,3-butanediol,1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2,4-pentanediol,2,5-hexanediol, 3-methyl-3-methoxybutanol, cyclohexanol and methylcyclohexanol.

Specific examples of the ether preferably include ethylene glycoldimethyl ether, diethylene glycol dimethyl ether, bis(2-propyl)ether,1,4-dioxane and THF.

Specific examples of the glycol monoalkyl ether include ethylene glycolmonoalkyl ether, diethylene glycol monoalkyl ether, triethylene glycolmonoalkyl ether, propylene glycol monoalkyl ether, dipropylene glycolmonoalkyl ether, ethylene glycol monoalkyl ether acetate, diethyleneglycol monoalkyl ether acetate, triethylene glycol monoalkyl etheracetate, propylene glycol monoalkyl ether acetate, dipropylene glycolmonoalkyl ether acetate and diethylene glycol methyl ethyl ether.

Specific examples of “ethylene glycol monoalkyl ether” herein includeethylene glycol monomethyl ether and ethylene glycol monobutyl ether.Specific examples of “diethylene glycol monoalkyl ether” herein includediethylene glycol monoethyl ether. Specific examples of “propyleneglycol monoalkyl ether” herein include propylene glycol monobutyl ether.Specific examples of “dipropylene glycol monoalkyl ether” herein includedipropylene glycol monomethyl ether. Specific examples of “ethyleneglycol monoalkyl ether acetate” herein include ethylene glycol monobutylether acetate. Specific examples of “diethylene glycol monoalkyl etheracetate” herein include diethylene glycol monoethyl ether acetate.Specific examples of “propylene glycol monoalkyl ether acetate” hereininclude propylene glycol monomethyl ether acetate, propylene glycolmonoethyl ether acetate and propylene glycol monobutyl ether acetate.Specific examples of “dipropylene glycol monoalkyl ether acetate” hereininclude dipropylene glycol monomethyl ether acetate.

Specific examples of the aromatic hydrocarbon include benzene, toluene,xylene, mesitylene, ethylbenzene, diethylbenzene, i-propylbenzene,n-propylbenzene, t-butylbenzene, s-butylbenzene, n-butylbenzene andtetralin.

Specific examples of the halogenated aromatic hydrocarbon includechlorobenzene. Specific examples of the aliphatic hydrocarbon includehexane and heptane. Specific examples of the halogenated aliphatichydrocarbon include chloroform, dichloromethane, carbon tetrachloride,dichloroethane, trichloroethylene and tetrachloroethylene. Specificexamples of the alicyclic hydrocarbon include cyclohexane and decalin.

Specific examples of the ketone include acetone, methyl ethyl ketone,methyl isobutyl ketone, cyclohexanone, cyclopentanone and methyl propylketone.

Specific examples of the acetate-based solvent include ethylene glycolmonomethyl ether acetate, propylene glycol monomethyl ether acetate,propylene glycol monoethyl ether acetate, methyl acetoacetate and1-methoxy-2-propyl acetate.

From a viewpoint of the compatibility with the polymerizable liquidcrystal compound, an amount of the solvent in the polymerizable liquidcrystal composition is preferably 30 to 96% by weight, furtherpreferably 50 to 90% by weight, and still further preferably 60 to 80%by weight, based on the total amount of the polymerizable liquid crystalcomposition.

The polymerizable liquid crystal composition of the invention maycontain a compound having optical activity. Addition of the compoundhaving optical activity to the liquid crystal composition results ininducing the liquid crystal polymerization film into twist alignment.The liquid crystal polymer can be used as a selective reflection filmand a negative C-plate in a wavelength region of 300 to 2,000nanometers.

Specific examples of the compound having optical activity include acompound having asymmetric carbon, an axial chirality compound having abinaphtyl structure and a helicene structure, and a planar chiralitycompound having a cyclophane structure. From a viewpoint of immobilizinga helical pitch of twist alignment, the compound having optical activityin the above case is preferably a polymerizable compound.

The liquid crystal polymer of the invention may contain a dichroic dye.The liquid crystal polymer forming a composite with the dichroic dye canbe used in the form of an absorptive polarizing plate.

The dichroic dye preferably has a maximum absorption wavelength in therange of 300 to 700 nanometers. As the dichroic dye, an acridine dye, anoxazine dye, a cyanine dye, a naphthalene dye, an azo dye, ananthraquinone pigment or the like can be utilized. Specific examples ofthe azo dye include a monoazo dye, a bisazo dye, a trisazo dye, atetrakisazo dye and a stilbeneazo dye.

The liquid crystal polymer of the invention may contain a fluorescentdye. The liquid crystal polymer forming a composite with the fluorescentdye can be used in the form of a polarizing light-emitting film and awavelength conversion film.

Substrate

Specific examples of material of the substrate include glass, plasticand metal. The glass or the metal may be subjected to slit-formprocessing on a surface thereof. The plastic may be subjected tostretching treatment and surface treatment such as hydrophilizingtreatment and hydrophobicizing treatment.

When the liquid crystal polymer having homogeneous alignment and tiltalignment is formed on the substrate, surface treatment is applied tothe substrate before the polymerizable liquid crystal composition isapplied to the substrate to induce alignment of the liquid crystalpolymer. Specific examples of the surface treatment include (a) a methodof applying rubbing onto a substrate, (d) a method of applying inclineddeposition of silicon oxide onto a substrate and (c) a method ofarranging a polymer coat onto a substrate and irradiating the polymercoat with polarized ultraviolet light.

The following procedure is one example of the rubbing:

(1) rubbing cloth formed of a raw material such as rayon, cotton andpolyamide is wound around a metallic roll or the like;

(2) the roll is brought into contact with the substrate; and

(3) the roll is moved in parallel to a surface of the substrate whilethe roll is rotated, or the substrate is moved with keepingimmobilization of the roll.

A coat of the polymer may be arranged on the substrate before rubbing toapply rubbing onto the coat. As the coat, a material called a rubbingalignment film of polyimide, polyamic acid, polyvinyl alcohol or thelike is used.

Defects of alignment of the liquid crystal polymer, or the like can beprevented by the rubbing.

The following procedure is one example of the irradiation with polarizedultraviolet light:

(1) a polymer coat called a photoalignment film is arranged on asubstrate;

(2) the substrate is irradiated with linear polarization having awavelength of 250 to 400 nanometers; and

(3) when necessary, heat treatment is applied thereto.

The photoalignment film is a film of polyimide, polyamic acid orpolyacrylate containing a photosensitive group, or the like. Thephotosensitive group is preferably a chalcone group, cinnamoyl or an azogroup.

The defects of alignment of the liquid crystal polymer, or the like canbe prevented by irradiation with polarized ultraviolet light, and thedefects of alignment by scraping or the like by the rubbing can also beprevented thereby.

Liquid Crystal Polymer

A liquid crystal polymer with a substrate of the invention is obtainedby the following steps:

(1) a polymerizable liquid crystal composition is applied onto asubstrate, and when necessary, the resulting material is dried to form acoating film; and

(2) the polymerizable liquid crystal composition is polymerized by meansof light, heat, a catalyst or the like in a state in which thepolymerizable liquid crystal composition is aligned to obtain a liquidcrystal polymer with a substrate.

Thus, the polymerizable liquid crystal composition in the coating filmis immobilized with keeping a liquid crystalline state.

Various coating methods are used for coating the substrate with thepolymerizable liquid crystal composition. From a viewpoint of uniformityof a film thickness of the polymerizable liquid crystal composition onthe substrate, as a coating method, a spin coating method, amicrogravure coating method, a gravure coating method, a wire-barcoating method, a dip coating method, a spray coating method, a meniscuscoating method and a die coating method are preferred.

Heat treatment during drying upon forming the liquid crystal polymerwith the substrate is preferably applied thereto for removing thesolvent. The heat treatment can be applied thereto by using a hot plateor a drying oven, or by blowing warm air or hot air, or the like.

A means such as an electron beam, ultraviolet light, visible light andinfrared light can be utilized for obtaining the liquid crystal polymerof the invention. A range of a wavelength of irradiation light forobtaining the liquid crystal polymer is 150 to 500 nanometers. A rangeof a wavelength of light is preferably 250 to 450 nanometers, andfurther preferably 300 to 400 nanometers.

As a light source of the light, a low-pressure mercury lamp, ahigh-pressure discharge lamp and a short arc discharge lamp can beutilized. Specific examples of the low-pressure mercury lamp include abactericidal lamp, a fluorescent chemical lamp and a black light.Specific examples of the high-pressure discharge lamp include a highpressure mercury lamp and a metal halide lamp. Specific examples of theshort arc discharge lamp include an ultra-high pressure mercury lamp, aXenon lamp and a Mercury-Xenon lamp.

The liquid crystal polymer can be arranged inside and outside a liquidcrystal cell of a liquid crystal display device. The liquid crystalpolymer can be arranged inside the liquid crystal cell because of smallvariation of retardation Re of the liquid crystal polymer by a heathistory and small elution of impurities from the liquid crystal polymerto liquid crystals.

A polarizing plate having a function of optical compensation or the likecan be produced by applying the polarizing plate as the substrate andforming the liquid crystal polymer. For example, a circularly polarizingplate can be produced by combining the liquid crystal polymer havingretardation of a ¼ wavelength plate with the polarizing plate.

Specific examples of the polarizing plate include an absorptivepolarizing plate in which iodine or a dichroic dye is doped and areflective polarizing plate such as a wire grid polarizing plate.

As a method of eliminating the liquid crystal polymerization film fromthe liquid crystal polymer with the substrate and fixing the film toanother substrate, the following method is known:

(1) a liquid crystal polymer with a substrate is laminated with asubstrate having an adhesive layer in such a manner that the liquidcrystal polymerization film is brought into contact with the adhesivelayer;

(2) the material laminated in such a manner that the liquid crystalpolymerization film is brought into contact with the adhesive layer ispeeled off in a place between a substrate portion of the liquid crystalpolymer with the substrate, and the liquid crystal polymerization film;and

(3) the liquid crystal polymerization film on the substrate having theadhesive layer is fixed to another substrate in a manner similar to thesteps (1) and (2) described above.

EXAMPLES

The invention is not limited only to Examples described to the public.

In Examples of the invention, “DCC” means 1,3-dicyclohexylcarbodiimide.

In Examples of the invention, “DMAP” means 4-dimethylaminopyridine.

In Examples of the invention, “Irg-907” means IRGACURE (trademark) 907(Irg-907) made by BASF Japan Ltd.

In Examples of the invention, “NCI-930” means ADEKARKLS (trademark)NCI-930 made by ADEKA Corporation.

In Examples of the invention, “FTX-218” means FUTARGENT (trademark)FTX-218 made by Neos Co., Ltd.

In Examples of the invention, “TEGOFlow 370” means TEGOFLOW (trademark)370 of Evonik Japan, Inc.

In Examples of the invention, “palladium on carbon” means P1528 made byTokyo Chemical Industry Co., Ltd.

Polymerization Conditions

A polymerizable liquid crystal composition was irradiated with lightfrom an ultra-high pressure mercury lamp for 30 seconds at roomtemperature under a nitrogen atmosphere to polymerize the composition.The composition was irradiated with the light from the ultra-highpressure mercury lamp to be 30 mW/cm² in irradiance of ultraviolet lighthaving a wavelength of 365 nm on a surface of the polymerizable liquidcrystal composition. As the ultra-high pressure mercury lamp, MultilightUSH-250BY made by Ushio Inc. was used. The irradiance was measured byusing Ultraviolet Intensity Meter UIT-150-A and Photodetector UVD-S365made by Ushio Inc. according to a user instruction.

Confirmation of Structure of Compound

A structure of a compound was confirmed by measuring proton NMR at 500MHz by using DRX-500 made by Bruker Corporation. A unit of a numericvalue as described below was ppm. Then, s, d, t and m stand for asinglet, a doublet a triplet and a multiplet, respectively.

Phase Transition Temperature

A sample was placed on a hot plate in a melting point apparatus, and atransition temperature was measured with a polarizing microscope. Thetransition temperature was measured while a temperature of the samplewas raised at a rate of 3° C. per minute.

Visual Observation Method

A substrate on which a phase difference film was formed was interposedbetween two polarizing plates arranged in a crossed Nicol state, and theresulting set was observed. The substrate was rotated in a horizontalplane to confirm a bright and dark state. The substrate on which thephase difference film was formed was observed by a polarizing microscopeto confirm existence or non-existence of alignment defects. A case wherea place through which light was observed was observed in a dark state orneither a light state nor a dark state was unable to be confirmed wasdeemed as “defective alignment.” A case other than “defective alignment”was deemed “non-defective alignment.”

Measurement of Film Thickness

A film thickness of the liquid crystal polymerization film was measuredaccording to the following procedures:

(1) a liquid crystal polymerization film was shaved off from a glasssubstrate with a liquid crystal film;

(2) a level difference between a portion having the liquid crystalpolymerization film and a portion having no liquid crystalpolymerization film was measured; and

(3) the resulting measured value was taken as a film thickness.

The level difference between the portions of the liquid crystal polymerwas measured by using Alpha-Step IQ made by KLA-Tencor Corporation.

Measurement by Ellipsometer

Retardation Re was measured by using OPTIPRO Ellipsometer made byShintech, Inc. Retardation Re was measured while an angle of incidentlight to a surface of the liquid crystal polymer was decreased from 90°.Wavelengths of light used for measurement were 450 nm, 550 nm and 650nm.

Evaluation of Birefringence Δn

Birefringence Δn for every wavelength was calculated by “(retardationRe)/(film thickness).”

Measurement of Luminance in Crossed Nicol State and Luminance inParallel Nicol State

Luminance in a crossed Nicol state and luminance in a parallel Nicolstate were evaluated by using a luminance meter by interposing, betweentwo polarizing plates of a polarizing microscope, a substrate on which aphase difference film was formed. As the luminance meter, YOKOGAWA3298F. was used. Luminance to be a minimum when the substrate washorizontally rotated was regarded as “luminance in the crossed Nicolstate.” Luminance to be a maximum when the substrate was rotated in ahorizontal plane was regarded as “luminance in the parallel Nicolstate.”

Preparation of Photo-Alignment Agent

A polymer represented by formula (J) was synthesized in a manner similarto the method in Example 9 in JP 2012-087286 A.

In formula (J), x was 0.1, and a weight average molecular weight was53,700. Then, 5% by weight of the polymer represented by formula (J) wasdissolved into 95% by weight of cyclopentanone, and a material obtainedby filtrating the resulting mixture with a filter was named asphoto-alignment agent (1). Here, the weight average molecular weight wasdetermined by a gel permeation chromatograph. LC-9A Gel PermeationChromatograph made by Shimadzu Corporation was used as the gelpermeation chromatograph. Shodex GF-7M HQ was used as a column of thegel permeation chromatograph. Shodex is a registered trademark of ShowaDenko K.K.

A temperature of the column during the development was set to 40° C. THFwas used as an eluent in GPC. On the above occasion, polystyrene havinga known molecular weight was used as a reference material fordetermining the weight average molecular weight. As the filter,13JP020AN made by Advantech Co., Ltd. was used. A pore size described onthe filter was 0.2 μm.

Adjustment of Photoalignment Film

A glass substrate with an alignment film subjected to polarizedultraviolet light treatment was prepared according to the followingsteps:

(1) photo-alignment agent (1) was spin-coated onto glass to prepare acoating film;

(2) a substrate having the coating film was left to stand on a hot plateat 100° C. for 60 seconds to remove a solvent from the coating film; and

(3) the coating film was irradiated with linearly polarized ultravioletlight having a wavelength in the vicinity of 313 nm at 200 mJ/cm² from adirection at 90° relative to a coated surface. The linearly polarizedultraviolet light was obtained by transmitting light from an ultra-highpressure mercury lamp to a wire grid polarizing plate. MultilightUSH-250BY made by Ushio Inc. was used as the ultra-high pressure mercurylamp. The wire grid polarizing plate was UVT300A made by Polatechno Co.,Ltd.

Example 1

Compound (1-1-1-1) was prepared according to the procedures describedbelow.

Compound ex-1 was synthesized in a manner similar to the methoddescribed in ACS Medicinal Chemistry Letters, 2010, 1(7), pp 345-349.

To 50 mL of dichloromethane, 5.0 g of compound ex-1, 2.0 g of2,7-dihydroxy-9-methylfluorene and 0.5 g of DMAP were added, and theresulting mixture was stirred under a nitrogen atmosphere while theresulting mixture was cooled. Then, 10 mL of a dichloromethane solutionin which 4.2 g of DCC was dissolved was added dropwise thereto. Afterdropwise addition, the resulting mixture was stirred at room temperaturefor 16 hours. A deposit precipitate was filtered off, and an organiclayer was washed with water and dried over anhydrous magnesium sulfate.Dichloromethane was distilled off under reduced pressure, and theresidue was purified by column chromatography and recrystallized inmethanol to obtain 5.6 g of compound (ex-2). Here, a packing material incolumn chromatography was silica gel. Here, an eluent was atoluene-ethyl acetate mixture (v/v=14/1).

To 56 mL of THF, 5.6 g of compound ex-2 and 0.3 g of palladium on carbonwere added, and the resulting mixture was stirred at room temperatureunder a hydrogen atmosphere for 24 hours. An insoluble matter wasfiltered off, and THF was distilled off under reduced pressure and theresulting material was dried under reduced pressure to obtain 3.8 g ofcompound (ex-3).

Compound ex-4 was synthesized in a manner similar to the methoddescribed in Journal of Polymer Science, Part A; Polymer Chemistry,2011, 49(3), pp 770-780.

To 40 mL of dichloromethane, 3.8 g of compound ex-3, 4.5 g of compoundex-4 and 0.4 g of DMAP were added, and the resulting mixture was stirredunder a nitrogen atmosphere while the resulting mixture was cooled.Then, 7 mL of a dichloromethane solution in which 3.3 g of DCC wasdissolved was added dropwise thereto. After dropwise addition, theresulting mixture was stirred at room temperature for 16 hours. Adeposit precipitated was filtered off, and an organic layer was washedwith water and dried over anhydrous magnesium sulfate. Dichloromethanewas distilled off under reduced pressure, and the residue was purifiedby column chromatography and recrystallized in methanol to obtain 5.6 gof compound (1-1-1-1). Here, a packing material in column chromatographywas silica gel. Here, an eluent was a toluene-ethyl acetate mixture(v/v=14/1).

A phase transition temperature and NMR analysis values of compound(1-1-1-1) were as described below.

A transition temperature from a crystal phase to a nematic phase incompound (1-1-1-1) was 111° C. A transition temperature from the nematicphase to an isotropic liquid in compound (1-1-1-1) was unable to beconfirmed at 250° C. or lower.

¹H-NMR (CDCl₃; δ ppm): 8.15 (d, 4H), 7.67 (d, 2H), 7.34 (d, 4H), 7.17(d, 6H), 7.01 (d, 2H), 6.97 (d, 4H), 6.41 (d, 2H), 6.16-6.08 (m, 2H),5.83 (d, 2H), 4.18 (t, 4H), 4.05 (t, 4H), 3.96-3.90 (m, 1H), 3.12 (t,4H), 2.93 (t, 4H), 1.88-1.81 (m, 4H), 1.77-1.70 (m, 4H), 1.58-1.44 (m,11H).

Example 2

Compound (1-1-2-1) was synthesized according to the procedures describedbelow.

Compound ex-5 was synthesized in a manner similar to the methoddescribed in Example 1 in JP 5310548 B.

Compound ex-6 was synthesized in a manner similar to the methoddescribed in Example 5 in JP 2016-47813 A.

To 221 mL of dichloromethane, 15.2 g of compound ex-5, 22.1 g ofcompound ex-6 and 1.7 g of DMAP were added, and the resulting mixturewas stirred under a nitrogen atmosphere while the resulting mixture wascooled. Then, 30 mL of a dichloromethane solution in which 14.9 g of DCCwas dissolved was added dropwise thereto. After dropwise addition, theresulting mixture was stirred at room temperature for 16 hours. Adeposit precipitated was filtered off, and an organic layer was washedwith water and dried over anhydrous magnesium sulfate. Dichloromethanewas distilled off under reduced pressure, and the residue was purifiedby column chromatography and recrystallized in methanol to obtain 16 gof compound (1-1-2-1). Here, a packing material in column chromatographywas silica gel. Here, an eluent was a toluene-ethyl acetate mixture(v/v=20/1).

A phase transition temperature and NMR analysis values of compound(1-1-2-1) were as described below.

A transition temperature from a crystal phase to a nematic phase incompound (1-1-2-1) was 116° C. A transition temperature from the nematicphase to an isotropic liquid in compound (1-1-2-1) was unable to beconfirmed at 250° C. or lower.

¹H-NMR (CDCl₃; δ ppm): 8.25 (d, 4H), 7.76 (d, 2H), 7.36 (s, 1H),7.23-7.16 (m, 10H), 6.86 (d, 4H), 6.40 (d, 2H), 6.16-6.08 (m, 2H), 5.82(d, 2H), 4.17 (t, 4H), 4.04-3.98 (m, 1H), 3.95 (t, 4H), 3.03 (t, 4H),2.90 (t, 4H), 1.84-1.77 (m, 4H), 1.76-1.68 (m, 4H), 1.58-1.42 (m, 11H).

Example 3

Compound (1-1-1-2) was synthesized according to the procedures describedbelow.

Compound ex-7 was synthesized in a manner similar to the methoddescribed in JP 2009-242540 A.

To 200 mL of dichloromethane, 18.8 g of compound ex-3, 20.0 g ofcompound ex-7 and 1.8 g of DMAP were added, and the resulting mixturewas stirred under a nitrogen atmosphere while the resulting mixture wascooled. Then, 33 mL of a dichloromethane solution in which 16.4 g of DCCwas dissolved was added dropwise thereto. After dropwise addition, theresulting mixture was stirred at room temperature for 16 hours. Adeposit precipitated was filtered off, and an organic layer was washedwith water and dried over anhydrous magnesium sulfate. Dichloromethanewas distilled off under reduced pressure, and the residue was purifiedby column chromatography and recrystallized in methanol to obtain 30.8 gof compound (1-1-1-2). Here, a packing material in column chromatographywas silica gel. Here, an eluent was a toluene-ethyl acetate mixture(v/v=9/1).

A phase transition temperature and NMR analysis values of compound(1-1-1-2) were as described below.

A transition temperature from a crystal phase to a nematic phase incompound (1-1-1-2) was 101° C. A transition temperature from the nematicphase to an isotropic liquid in compound (1-1-1-2) was unable to beconfirmed at 250° C. or lower.

¹H-NMR (CDCl₃; δ ppm): 8.15 (d, 4H), 7.67 (d, 2H), 7.34 (d, 4H), 7.17(d, 6H), 7.01 (d, 2H), 6.97 (d, 4H), 6.42 (d, 2H), 6.16-6.08 (m, 2H),5.83 (d, 2H), 4.26 (t, 4H), 4.10 (t, 4H), 3.97-3.91 (m, 1H), 3.12 (t,4H), 2.93 (t, 4H), 1.98-1.87 (m, 8H), 1.49 (d, 3H).

Example 4

Compound (1-1-5-1) was synthesized according to the procedures describedbelow.

Compound ex-8 was synthesized in a manner similar to the methoddescribed in Example 5 in JP 2016-047813 A.

To 100 mL of dichloromethane, 2.3 g of 2,7-dihydroxy-9-methylfluorene,10.0 g of compound ex-8 and 0.5 g of DMAP were added, and the resultingmixture was stirred under a nitrogen atmosphere while the resultingmixture was cooled. Then, 10 mL of a dichloromethane solution in which4.9 g of DCC was dissolved was added dropwise thereto. After dropwiseaddition, the resulting mixture was stirred at room temperature for 16hours. A deposit precipitated was filtered off, and an organic layer waswashed with water and dried over anhydrous magnesium sulfate.Dichloromethane was distilled off under reduced pressure, and theresidue was purified by column chromatography and recrystallized inmethanol to obtain 8.2 g of compound (1-1-5-1). Here, a packing materialin column chromatography was silica gel. Here, an eluent was atoluene-ethyl acetate mixture (v/v=9/1).

A phase transition temperature and NMR analysis values of compound(1-1-5-1) were as described below.

A transition temperature from a crystal phase to a nematic phase incompound (1-1-5-1) was 127° C. A transition temperature from the nematicphase to an isotropic liquid in compound (1-1-5-1) was unable to beconfirmed at 250° C. or lower.

¹H-NMR (CDCl₃; δ ppm): 7.68 (d, 2H), 7.18 (d, 2H), 7.11 (d, 4H), 7.06(d, 2H), 6.81 (d, 4H), 6.42 (d, 2H), 6.16-6.08 (m, 2H), 5.83 (d, 2H),4.83-4.77 (m, 2H), 4.21-4.13 (m, 5H), 3.93 (t, 4H), 2.89 (t, 4H),2.62-2.53 (m, 6H), 2.24-2.18 (m, 4H), 2.12-2.04 (m, 4H), 1.83-1.68 (m,12H), 1.63-1.42 (m, 15H).

Preparation of Polymerizable Liquid Crystal Composition Example 5

Structures of compounds (M-2-1-1) and (M-2-21-1) each being a componentof the polymerizable liquid crystal composition are described below.

Table 1 and Table 2 show compounds and contents thereof in thepolymerizable liquid crystal compositions confirmed in Examples of theinvention. In addition, “-” in the Tables means no addition.

TABLE 1 Name of Content and Content and Content of polymerizable name ofContent of Content of name of Content and cyclohexanone liquid crystalcompound compound compound polymerization name of used as composition(1) (M-2-1-1) (M-2-21-1) initiator surfactant solvent S-1 3.4% by 11.9%by 1.7% by 1.02% by 0.05% by weight 81.93% by weight of weight weightweight of of weight compound NCI-930 FTX-218 (1-1-1-1) S-2 6.8% by 8.5%by 1.7% by 1.02% by 0.05% by weight 81.93% by weight of weight weightweight of of weight compound Irg-907 TEGOFlow 370 (1-1-1-1) S-3 3.6% by14.4% by — 1.08% by 0.05% by weight 80.87% by weight of weight weight ofof weight compound Irg-907 TEGOFlow 370 (1-1-2-1) S-4 6.8% by 8.5% by1.7% by 1.02% by 0.05% by weight 81.93% by weight of weight weightweight of of weight compound NCI-930 TEGOFlow 370 (1-1-1-2) S-5 1.7% by13.6% by 1.7% by 1.02% by 0.05% by weight 81.93% by weight of weightweight weight of of weight compound NCI-930 TEGOFlow 370 (1-1-5-1)

TABLE 2 Name of Content and polymerizable Content of Content of name ofContent and Content of liquid crystal compound compound polymerizationname of cyclohexanone composition (M-2-1-1) (M-2-21-1) initiatorsurfactant used as solvent SC-1 15.3% by 1.7% by 1.02% by 0.05% by81.93% by weight weight weight of weight of weight Irg-907 FTX-218 SC-28.5% by 8.5% by 1.02% by 0.05% by 81.93% by weight weight weight ofweight of weight Irg-907 TEGOFlow 370

Preparation of Liquid Crystal Polymer Example 6

Liquid crystal polymer (F-1) was prepared according to the proceduresdescribed below:

(1) liquid crystal composition (S-1) was applied onto a glass substratewith an alignment film subjected to polarized ultraviolet lighttreatment by spin coating;

(2) the substrate was heated on a hot plate at 80° C. for 3 minutes;

(3) subsequently, the substrate was cooled at room temperature for 3minutes; and

(4) the substrate was polymerized by irradiation with ultraviolet lightin air at room temperature.

Liquid crystal polymer (F-1) had homogeneous alignment. Liquid crystalpolymer (F-1) was non-defective alignment.

Example 7

Liquid crystal polymers (F-2) to (F-5) were obtained by using liquidcrystal compositions (S-2) to (S-5) in place of liquid crystalcomposition (S-1) according to the procedures described in Example 6.Liquid crystal polymers (F-2) to (F-5) had homogeneous alignment. Liquidcrystal polymers (F-2) to (F-5) were non-defective alignment.

Comparative Example 2

Liquid crystal polymer (CF-1) was obtained by using liquid crystalcomposition (SC-1) in place of liquid crystal composition (S-1)according to the procedures described in Example 6. Liquid crystalpolymer (CF-2) was obtained by using liquid crystal composition (SC-2)in place of liquid crystal composition (S-1) according to the proceduresdescribed in Example 6.

Optical Characteristics of Optically Anisotropic Film

TABLE 3 Name of Name of polymerizable liquid crystal liquid crystalRetardation Birefringence Front polymer composition Re Δn contrast F-1S-1 136.3 0.18 5500 F-2 S-2 138.9 0.20 6100 F-3 S-3 140.3 0.18 5500 F-4S-4 142.4 0.20 6100 F-5 S-5 139.1 0.17 5200 CF-1 SC-1 139.7 0.17 4900CF-2 SC-2 141.0 0.20 4900

Table 3 describes retardation Re of light having a wavelength of 550 nm,birefringence Δn of light having a wavelength of 550 nm and frontcontrast for every liquid crystal polymer.

Table 3 shows that the front contrast in liquid crystal polymers (F-1)to (F-5) each is significantly higher than the front contrast in liquidcrystal polymers (CF-1) and (CF-2).

Thus, the liquid crystal polymer having high front contrast can beobviously obtained from the polymerizable liquid crystal compositioncontaining the polymerizable liquid crystal compound of the invention.

What is claimed is:
 1. A polymerizable liquid crystal compound,represented by formula (1):

wherein, in formula (1), W¹ is independently hydrogen, fluorine, alkylhaving 1 to 5 carbons, alkenyl having 2 to 5 carbons or fluoroalkylhaving 1 to 5 carbons, A¹ is independently 1,4-phenylene,1,4-cyclohexylene or naphthalene-2,6-diyl, and in the rings, at leastone hydrogen may be replaced by fluorine, chlorine, trifluoromethyl,alkyl having 1 to 5 carbons, alkoxy having 1 to 5 carbons,alkoxycarbonyl having 1 to 5 carbons or alkanoyl having 1 to 5 carbons,Z¹ is independently —CH₂CH₂—, —COO—, —OCO—, —CH₂O—, —OCH₂—, —OCH₂CH₂O—,—CH═CHCOO—, —OCOCH═CH—, —CH₂CH₂COO—, —OCOCH₂CH₂—, —CH₂CH₂OCO— or—COOCH₂CH₂—, m and n are independently an integer from 0 to 7, in whichan expression: 3≦m+n≦8 holds, Y¹ is independently a single bond, —O—,—COO—, —OCO— or —OCOO—, Q¹ is independently an single bond or alkylenehaving 1 to 20 carbons, and in the alkylene, at least one piece of —CH₂—may be replaced by —O—, —OCO—, —OCO—, —CH═CH— or —CH≡CH—, and PG isindependently a functional group represented by any one of formula(PG-1) to formula (PG-9):

wherein, in formula (PG-1) to formula (PG-9), R¹ is independentlyhydrogen, halogen, methyl, ethyl or trifluoromethyl.
 2. Thepolymerizable liquid crystal compound according to claim 1, wherein atleast one of W¹ is alkyl having 1 to 5 carbons, and at least one of Z¹is —CH₂CH₂COO— or —OCOCH₂CH₂—.
 3. The polymerizable liquid crystalcompound according to claim 1, wherein PG is a functional grouprepresented by formula (PG-1).
 4. The polymerizable liquid crystalcompound according to claim 1, wherein at least one of Z¹ is—CH₂CH₂COO—, and at least one of Z¹ is —OCOCH₂CH₂—.
 5. A polymerizableliquid crystal composition, containing the polymerizable liquid crystalcompound according to claim
 1. 6. The polymerizable liquid crystalcomposition according to claim 5, containing 5 to 70 parts by weight ofa polymerizable liquid crystal compound represented by formula (1) whenthe total amount of the polymerizable liquid crystal compound in apolymerizable liquid crystal composition is taken as 100 parts byweight.
 7. A liquid crystal polymer, obtained by curing thepolymerizable liquid crystal composition according to claim
 5. 8. Theliquid crystal polymer according to claim 7, wherein liquid crystalmolecules were immobilized in a state in which the liquid crystalmolecules are aligned by a photoalignment film.
 9. A phase differencefilm, comprising the liquid crystal polymer according to claim
 7. 10. Adisplay device, having the liquid crystal polymer according to claim 7.